%D 2015
%T Selective adsorption of CO2 on a regenerable amine-bentonite hybrid adsorbent
%V 107
%O cited By 26
%R 10.1016/j.clay.2015.01.030
%A A.E.I. Elkhalifah
%A M. Azmi Bustam
%A A.M. Shariff
%A T. Murugesan
%L scholars5975
%P 213-219
%I Elsevier Ltd
%X The ability of magnesium form of bentonite modified by monoethanolammonium cations (MEA+-Mg-bentonite) to reversibly and selectively adsorb CO2 over other light gases, such as CH4 and N2 has gravimetrically been investigated using a Magnetic Suspension Balance (MSB) equipment. Before CO2 adsorption measurements, untreated bentonite and MEA+-Mg-bentonite were characterized by XRD, FTIR, TGA and BET techniques to establish their structural characteristics, thermal stability and specific surface area and porosity characteristics. The results showed that MEA+-Mg-bentonite adsorbed higher CO2 amount compared to untreated bentonite under similar conditions. The equilibrium isotherms for CO2 adsorption on untreated bentonite and MEA+-Mg-bentonite were measured at 25, 50 and 75°C and a pressure range of 01.0bar. It was found that MEA+-Mg-bentonite has static CO2 adsorption capacities of 0.79, 0.69 and 0.56mmol/g, compared to 0.45, 0.36 and 0.30mmol/g for untreated bentonite at temperatures of 25, 50 and 75°C and a pressure of 1bar, respectively. The calculated values of the thermodynamic parameters revealed that the process involving CO2 adsorption on MEA+-Mg-bentonite adsorbent was a physical, spontaneous and exothermic. Moreover, the results showed moderate and slightly high equilibrium selectivities for CO2 over CH4 on MEA+-Mg-bentonite with the values of 1.36, 4.85 and 3.43 at 25, 50 and 75°C, respectively. However, MEA+-Mg-bentonite showed equilibrium selectivity for CO2 over N2 as high as 13.79, 9.91 and 6.32 at 25, 50 and 75°C, respectively. Regenerative ability in short runs of isothermal CO2 adsorption-desorption cycles revealed that MEA+-Mg-bentonite adsorbent was able to undergo several CO2 adsorption-desorption cycles without noticeable decrease in its adsorption capacity. Clearly, amine-bentonite hybrid adsorbents are promising inexpensive materials for CO2 capture. © 2015 Elsevier B.V.
%J Applied Clay Science
%K Adsorbents; Adsorption; Adsorption isotherms; Bentonite; Catalyst selectivity; Desorption; Ethanolamines; Hybrid materials; Suspensions (components); Thermodynamics, Adsorption measurement; Adsorption-desorption cycles; Equilibrium isotherms; Magnetic suspension balance; Regenerability; Specific surface area and porosities; Structural characteristics; Thermodynamic parameter, Carbon dioxide, adsorption; bentonite; carbon dioxide; desorption; isotherm; magnesium; thermodynamics